Out-of-Bounds Read in Linux kernel (CVE-2021-47102)
Summary
Vulnerability in Linux kernel (CVE-2021-47102). Confidential information can be exposed externally.
Original description
The description as published by the source.
In the Linux kernel, the following vulnerability has been resolved:
net: marvell: prestera: fix incorrect structure access
In line:
upper = info->upper_dev;
We access upper_dev field, which is related only for particular events
(e.g. event == NETDEV_CHANGEUPPER). So, this line cause invalid memory
access for another events,
when ptr is not netdev_notifier_changeupper_info.
The KASAN logs are as follows:
[ 30.123165] BUG: KASAN: stack-out-of-bounds in prestera_netdev_port_event.constprop.0+0x68/0x538 [prestera]
[ 30.133336] Read of size 8 at addr ffff80000cf772b0 by task udevd/778
[ 30.139866]
[ 30.141398] CPU: 0 PID: 778 Comm: udevd Not tainted 5.16.0-rc3 #6
[ 30.147588] Hardware name: DNI AmazonGo1 A7040 board (DT)
[ 30.153056] Call trace:
[ 30.155547] dump_backtrace+0x0/0x2c0
[ 30.159320] show_stack+0x18/0x30
[ 30.162729] dump_stack_lvl+0x68/0x84
[ 30.166491] print_address_description.constprop.0+0x74/0x2b8
[ 30.172346] kasan_report+0x1e8/0x250
[ 30.176102] __asan_load8+0x98/0xe0
[ 30.179682] prestera_netdev_port_event.constprop.0+0x68/0x538 [prestera]
[ 30.186847] prestera_netdev_event_handler+0x1b4/0x1c0 [prestera]
[ 30.193313] raw_notifier_call_chain+0x74/0xa0
[ 30.197860] call_netdevice_notifiers_info+0x68/0xc0
[ 30.202924] register_netdevice+0x3cc/0x760
[ 30.207190] register_netdev+0x24/0x50
[ 30.211015] prestera_device_register+0x8a0/0xba0 [prestera]
Source: NIST National Vulnerability Database NVD
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2021-47102 has been found in Linux kernel.
Confidential information can be exposed externally. CVSS score: 7.1/10.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "Linux kernel CVE-2021-47102" on the vendor's site.
CVE-2021-47102 (Linux kernel) — CWE-125 / CVSS v3 7.1
Attack vector: local / no user interaction
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
Out-of-bounds read (CWE-125) exists in Linux kernel.
Check the vendor advisory for the affected versions of Linux kernel.
Severity: High (CVSS 7.1/10). Confidential information can be exposed externally.
Update to the patched release per vendor advisory.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Audit SBOM/dependencies to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
-
1Identify exposure identify
Audit SBOM/dependencies for affected components.資産台帳・SBOM・依存マニフェストで Linux kernel を使っているサービスとバージョンを洗い出す。
-
2Post-deployment verification verify
Confirm patched version is live in productionパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。
Fix status by distribution
Fixed packages published by each distribution for this CVE
- Debian DEBIAN-CVE-2021-47102 linux Fixed in: 5.15.15-1
- Ubuntu UBUNTU-CVE-2021-47102 linux-hwe-edge
References
- exploit git.kernel.org
- exploit git.kernel.org